Reading Level
Where your text needs more reading ability than lower secondary education, you owe the reader either supplemental content or a simpler version. Lower secondary education is measured in years of school rather than in age. Nine years of school in total. The first six are primary and lower secondary is years seven to nine, so the bar is text somebody can read by the end of those nine years rather than after them. Proper names and titles come out of the text before you assess it, and titles here means the names of books, documents and films rather than headings or job titles. There are three ways to satisfy this, not two. Write the original simply enough, publish a simpler version alongside it, or add supplemental content.
Why it matters
W3C's explanation turns on decoding. Recognizing a written word and matching it to its sound has to be automatic for reading to be fluent, and doing it word by word eats the mental energy the reader needed for the meaning. That is why a hard sentence is not only slower, it is emptier. And the objection that your readers are all professionals does not hold. W3C answers it directly. There are people with reading disabilities among highly educated readers with specialist knowledge of the subject.
Who this rule protects
People with cognitive and learning disabilities, people with low literacy, and readers working in a second language. W3C also notes that reading disabilities turn up among expert readers, so the audience is not who you would guess.
How to check it yourself
- Read the page aloud and notice where you stop and go back to catch the meaning.
- Strip out proper names and the titles of documents before you judge it, because the criterion does.
- Check sentence length against W3C's own writing guidance. Twenty-five words for English, and no more than two conjunctions in a sentence. These are drafting targets inside a technique rather than a threshold the criterion sets, so a longer sentence is a prompt to reread it, not a finding.
- For a multilingual page, assess each language making up 5 percent or more of the content in full sentences or paragraphs, and judge the page on the worst result. Scattered individual words in another language do not trigger a separate assessment.
- Measure readability, then treat the number as a steer rather than a verdict. W3C's techniques ask you to measure it and name no particular formula, and no score tells you whether a reader could actually use the page.
Failures we see most often
- Dense legal or technical prose appears with no plain-language summary, no simpler version and no supplemental content anywhere.
- Sentences carry three clauses and two conditions each, so the reader has to hold too much at once.
- A grade-level score gets chased instead of the meaning, so the sentences get shorter and the page gets no easier to follow.
Who this one is for
Read from this rule's own note above, so the grouping and the note cannot disagree.
- Cognitive and learningpeople for whom the difficulty is understanding, remembering, or staying with it
How to fix it
- Add a plain-language summary above the dense content rather than replacing it.
- Shorten sentences, use active voice, and put the answer before the explanation.
- Add supplemental content instead of rewriting. An illustration of a process, an audio version, or a summary paragraph all count, and so does a sign language version, which is a documented route most people would never guess at.
Step-by-step fix guides (5)
Passes vs. fails
Passes
The same page adds a plain-language summary at the top, saying in ordinary words what the terms actually mean.
Fails
A terms page runs on unbroken subordinate clauses and undefined legal terms, with nothing beside it.
In audits and lawsuits
This is Level AAA, and one of the criteria that makes site-wide AAA impractical, though not for the reason people assume. A contract or a scientific paper usually cannot be rewritten to nine years of schooling without ceasing to be what it is. It never has to be. A plain-language summary published beside it satisfies the rule and the source text stays exactly as it was. Readability scores are worth being precise about, because both readings are half right. W3C mandates no particular formula, and its own techniques tell you to measure the readability of the text and of any summary you add, so a score is a legitimate instrument and a poor verdict. It cannot tell you whether a reader can use the document, which is the thing the criterion is actually about. One useful specific for multilingual sites. Any language making up 5 percent or more of a page in full sentences or paragraphs gets assessed, and the page is judged on whichever language scores worst.